1. Field of the Invention
The present invention relates to an apparatus for generating vibrations.
2. Description of the Related Art
An apparatus for generating vibrations, a component for converting electrical energy into mechanical vibrations by using a genetic principle of the generation of electromagnetic force, is installed in a portable phone so as to be used for silently notifying a user of receipt of an incoming call.
The rapid expansion of the cellular phone market has promoted the addition of a variety of functions to portable phones. In line with this trend, components of portable phones have been required to be smaller and have high quality. In the case of an apparatus for generating vibrations, the development of a product having a novel structure that may improve shortcomings of existing products and having remarkably improved quality has been required.
As portable phones having large LCD screens have been increasingly launched onto the market in recent years, a touch screen scheme has been adopted and an apparatuses for generating vibrations have also been used to generate vibrations in the event of a touch.
An apparatus for generating vibrations used in portable phones employing a touch screen is more frequently used in the event of a touch than in the event of receipt of an incoming call, so it is required to have a longer operational lifespan and a fast response speed in line with a speed at which a user touches a touch screen.
To meet the requirements of lifespan and responsiveness, currently, portable phones employing a touch screen also employ a linear vibrator.
Rather than using a principle of a motor rotating an unbalanced weight, in a linear vibrator, a mass body hanging on a spring installed therein makes a linear resonant motion by electromagnetic force generated by a coil and a magnet to generate vibrations.
Alternatively, a piezoelectric element may be used as an actuator to enable a mass body to make a linear resonant motion, according to contraction and expansion of the piezoelectric element to generate vibrations.
As the elastic member, a spring is generally used, and a leaf spring, a coil spring, or the like, is used. However, a lifespan of a spring is limited due to fracture (or destruction) of the spring. Also, when physical properties of a spring are changed due to a climate condition, or the like, the spring is readily fractured.
In addition, when a spring is abnormal (i.e., distorted, horizontally shaken, or the like), vibrations may be weakened noise may be generated.